The present invention relates to a system and a method for removing adhering surface-treating aqueous solutions from barrels and their loads of articles in bulk after electroplating and/or chemical surface treatments and the recovery of the solutions. More particularly, the invention relates to a system and a method for removing adhering surface-treating aqueous solutions from barrels and their loads of articles in bulk after electroplating and/or chemical surface treatments and their recovery with conveying means, traveling hoisting carriages, treatment stations, barrel aggregates with perforated walls, solution containers and connected tubular conduits.
Systems and methods for removing adhering surface treating aqueous media from objects and their recovery are known. This recovery is particularly required in connection with surface treatment procedures for loads of articles in bulk processed in so-called plating barrels. Such barrels and their loads drag out considerable quantities of treatment solutions which are drastically diluted in subsequent water rinsing steps (up to ratios of 1:1000 and more), and thereby nullified as a chemical solution to be used again. Further, the contaminated rinsing waters have to be supplied to decontaminating waste water treatment systems, thereby causing additional high expenses. Conventional stand rinse baths are used to compensate evaporation losses of high temperature treatment solutions. Even in such exceptional cases the main part of the drag-out quantities has to be decontaminated in waste water treatment systems. The object of the German Offenlegungsschrift No. 2,758,550 has a different proposal for reducing the previously mentioned disadvantages. This system partially removes the drag-out quantity of treatment solution by aspiration. The aspiration process has to be separately performed in an additional station of the plating plant directly attached to the tank containing the treatment solution and it must be arranged with means resupplying continuously via conduits the aspirated liquid medium into its original container.
U.S. Pat. No. 4,469,526 presents another proposal to solve the above mentioned problem. The barrel aggregate containing the load of articles in bulk is lifted above the container filled with the treatment solution. Two semicircular shells placed on a traveling carriage move horizontally and embrace completely the barrel forming a closed circular chamber all around the barrel. A small gap remains open at the bottom between both semicircular halves of the chamber. Pressurized gas (air) and rinsing water are alternately and periodically supplied to said chamber. A gas stream is blown through said narrow gap so that adhered treating solution is removed from the load and the barrel areas which are mainly around the gap and flows directly back to the container through said gap. The disadvantages of this system are obvious. The restricted zone around the gap from which the treatment solution is withdrawn results in a low efficiency of the system. The movement sequence of both semicircular chamber halves has to be program controlled in accordance with the barrel hoisting and lowering as well as with the alternately and periodically processed gas blowing and water rinsing steps. The guiding and supporting mechanism mounted on the carriage for the programmed movements of both semicircular chamber halves is complicated, heavy, difficult to maintain and, consequently, expensive. Furthermore, the lower inside regions of both chamber halves are covered by the blowing and rinsing steps with partially diluted treatment solutions. The remains of the solutions on the lower chamber halves will drip during the carriage movements along the plating plant into the different containers with different treatment solutions and contaminate or distabilize them.